Method and system for server-side message handling in a low-power wide area network

ABSTRACT

A network device may be operable to manage a network connection of customer premise equipment (CPE). While the CPE is operating in a normal mode of operation, the network device may communicate with the CPE utilizing one or more messages of a first type. While the CPE is operating in a low-power mode of operation, the network device may communicate with the CPE utilizing one or more messages of a second type. The network device may be operable to determine a particular program identifier to be utilized for messages the first type of message, and transmit such message(s) to the CPE. The message(s) transmitted while the CPE is in a low-power mode may comprise MPEG-TS packets having the particular program identifier. The message(s) transmitted while the CPE is not in the low-power mode may comprises MPEG-TS packets not having the particular program identifier.

This patent application makes reference to, claims priority to andclaims benefit from U.S. Provisional Patent Application Ser. No.61/547,663 filed on Oct. 14, 2011; U.S. Provisional Patent ApplicationSer. No. 61/555,550 filed on Nov. 4, 2011; and U.S. Provisional PatentApplication Ser. No. 61/569,346 filed on Oct. 14, 2011.

Each of the above applications is hereby incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to networking. Morespecifically, certain embodiments of the invention relate to a methodand system for Server-Side Message Handling in a Low-Power Wide AreaNetwork.

BACKGROUND OF THE INVENTION

Existing networks consume too much power. Further limitations anddisadvantages of conventional and traditional approaches will becomeapparent to one of skill in the art, through comparison of such systemswith some aspects of the present invention as set forth in the remainderof the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for server-side message handling in alow-power wide area network, substantially as shown in and/or describedin connection with at least one of the figures, as set forth morecompletely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts an exemplary DOCSIS network which may take advantage ofaspects of the invention.

FIG. 2 depicts a cable modem as an example of customer premise equipment(CPE).

FIG. 3 depicts a cable set-top box as an example of customer premiseequipment (CPE).

FIG. 4 depicts a cable gateway as an example of customer premiseequipment (CPE).

FIG. 5A depicts an exemplary PHY of a CPE which supports low-power widearea networking.

FIG. 5B illustrates an exemplary PHY which is operable to detectphysical layer “special messages.”

FIG. 6 depicts an exemplary medium access controller (MAC) of a CPEwhich supports low-power wide area networking.

FIG. 7 depicts a receive portion of a network device which is operableto communicate with customer premise equipment that supports apower-saving mode of operation.

FIG. 8 depicts a portion of a transmitter of a network device which isconfigurable based on a mode of operation of customer premise device towhich the network device is transmitting.

FIG. 9 is a flowchart illustrating exemplary steps for managing powerconsumption via special messaging.

FIG. 10 is a flowchart illustrating exemplary steps performed in alow-power wide area network.

FIG. 11 is a flowchart illustrating exemplary steps performed in alow-power wide area network.

FIG. 12A is a flowchart illustrating exemplary steps managing deviceregistration in a low-power wide area network.

FIG. 12B is a flowchart illustrating exemplary steps managing deviceregistration in a low-power wide area network.

DETAILED DESCRIPTION OF THE INVENTION

As utilized herein the terms “circuits” and “circuitry” refer tophysical electronic components (i.e. hardware) and any software and/orfirmware (“code”) which may configure the hardware, be executed by thehardware, and or otherwise be associated with the hardware. As utilizedherein, “and/or” means any one or more of the items in the list joinedby “and/or”. As an example, “x and/or y” means any element of thethree-element set {(x), (y), (x, y)}. As another example, “x, y, and/orz” means any element of the seven-element set {(x), (y), (z), (x, y),(x, z), (y, z), (x, y, z)}. As utilized herein, the terms “block” and“module” refer to functions than can be implemented in hardware,software, firmware, or any combination of one or more thereof. Asutilized herein, the term “exemplary” means serving as a non-limitingexample, instance, or illustration. As utilized herein, the terms“e.g.,” and “for, example” introduce a list of one or more non-limitingexamples, instances, or illustrations.

Aspects of the invention may enable the reception and processing of“special messages” (e.g., “wake up” and/or “go to sleep” messages) by aphysical layer transceiver (PHY) of a set-top box, a modem, or a gateway(collectively referred to as “customer premise equipment” (CPE)) tocontrol a mode of operation of components of the CPE. For example,processing of special messages may control a mode of operation of amedium access controller (MAC) in a cable modem, a video decoder in aSTB, or of both a MAC and video decoder in a gateway (a gateway mayperform functions of both a cable modem and STB). In this regard,whether components of a CPE are in a power-saving mode of operation or anormal mode of operation may be controlled via such special messages.

Although cable/DOCSIS networks and equipment (e.g., the CMTS 114 of FIG.1, the cable modem of FIG. 2, the cable STB of FIG. 3, and the cablegateway of FIG. 4) are utilized herein for illustration, the inventionis not so limited, and may be applicable to other networks. For example,aspects of the invention may be applicable to non-DOCSIS cabletelevision networks, satellite television networks, terrestrialtelevision networks, “Fiber to the X” (FTTX) networks (e.g., FIOS andU-VERSE), and/or other broadcast and/or wide-area networks.

FIG. 1 depicts an exemplary DOCSIS network which may take advantage ofaspects of the present invention. Shown in FIG. 1 is a terrestrialtelevision antenna 102, a satellite dish 104, an Internet Protocol (IP)network 106, a headend 108, a wide area network (e.g., hybridfiber-coaxial (HFC) network) 118, a gateway 120, end systems 126 a and126 b (e.g., computers), end systems 128 a and 128 b (e.g.,televisions), a cable modem 122 b, and a set-top box 124 b. The headend108 comprises a switch 110, a video modulator 112, a cable modemtermination system (CMTS) 114, and a splitter/combiner 116. The gateway120 may be an instance of the gateway 120 described below with respectto FIG. 4, and may comprise a cable modem module 122 a, and a set-topbox module 124 a. Each of cable modems 122 a and 122 b may be aninstance of the cable modem module 122 described with respect to FIG. 2.Each of set-top boxes 124 a and 124 b may be an instance of the set-topbox module 124 described with respect to FIG. 3.

For downstream traffic, the headend 108 may receive television signalsvia the antenna 102 and the satellite dish 104, and may receive data viathe IP network 106. The switch 110 may convey the television signals tothe video modulator 112 and the data to the CMTS 114. The videomodulator 112 may modulate the received television signals onto acarrier. The CMTS 114 may modulate the received data onto a carrier. Themodulation depth and/or other characteristics of the signal generated bythe CMTS may depend on whether the signal is to be communicated to acustomer premise device operating in a low-power mode, as describedbelow. The splitter/combiner 116 may combine the outputs of the videomodulator 112 and the CMTS 114 and output the combined signal onto thewide area network (WAN) 118 for distribution to CPE. The cable modems122 a and 122 b may process the portion of the combined signal thatcarries the data from the CMTS 114, and the set-top box modules 124 aand 124 b may process the portion of the combined signal that carriesthe video from the video modulator 112.

For upstream data, the end systems 126 a and 126 b may transmit packetsto the cable modem 122 a and 122 b, respectively, which may thenmodulate the packets onto a carrier for transmission via the WAN 118.The splitter/combiner 116 may then convey the data to the CMTS 114. TheCMTS 114 may process the data signals (e.g., verify that they came froma registered cable modem) and convey the data to the IP network 106. Themanner in which the signals are processed by the CMTS 114 may depend onwhether the device that transmitted the signals was operating in alow-power mode, as described below.

The CMTS 114 may manage connections to the cable modems 122 a and 122 b.This may include, for example: participating in ranging operations tocontrol the power at which the cable modems 122 a and 122 b transmit;forwarding of dynamic host configuration protocol (DHCP) messagesbetween a DHCP server and the cable modems 122 a and 122 b; forwardingof time of day messages between a time of day server and the cablemodems 122 a and 122 b; and managing registration of the cable modems122 a and 122 b to grant the cable modems network (e.g., Internet)access. The registration process for a cable modem 122 may comprise thecable modem 122 sending a registration request along with itsconfiguration settings, and the CMTS 114 accepting or rejecting thecable modem based on the configuration settings. The registrationprocess may additionally comprise an exchange of security keys,certificates, or other authentication information.

Conventionally, after a cable modem has successfully registered with theCMTS 114, the CMTS 114 will deregister the cable modem if the cablemodem does not communicate with the CMTS 114 for a predetermined periodof time. Accordingly, aspects of the present invention may enable acable modem 122 and the CMTS 114 to coordinate the cable modem 122operating in a low-power mode (“sleeping”) without being deregistered bythe CMTS 114. Such coordination between the cable modem 122 and the CMTS114 may be accomplished through communication of one or more specialmessages, as is described, for example, with respect to FIG. 5A and/orFIG. 5B.

Aspects of the invention may enable media access planning in adownstream direction. In this regard, the CMTS 114 may communicate(e.g., via one or more special messages) with CPEs (e.g., cable modems)that it serves to coordinate when and how (e.g., on which channel(s))the CMTS 114 will communicate with the CPEs. Downstream planning mayenable a CPE to sleep until the next time at which the plan requires itto listen on the channel(s).

Aspects of the invention may enable the CMTS 114 to dedicate a timeslotoccurring at fixed and/or deterministic intervals for the transmissionof special messages to one or more sleeping CPEs. Such a scheme may beanalogous to an unsolicited grant service, but in the downstreamdirection. Accordingly, a CPE (e.g., cable modem 122, set-top box 124,or gateway 120) may sleep for the fixed and/or deterministic timebetween occurrences of the timeslot, wake up and listen to the channelduring the timeslot, and then go back to sleep until the next occurrenceof the timeslot. Such dedicated timeslots in the downstream directionmay coincide in time, and/or have a fixed and/or deterministic timerelationship to, unsolicited grants in the upstream direction. In thismanner, if there is no upstream activity during the correspondingunsolicited grant, then adjustments may be made to, for example, theduration of the timeslot, the interval between occurrences of thetimeslot, etc. The special messages communicated during occurrences ofthe timeslot may, for example, contain wake up messages. As anotherexample, the special messages communicated during occurrences of thetimeslot may comprise data communicated to or from “always on” endsystems (e.g., appliances, utility meters, etc.) that may need tocommunicate over the WAN via a CPE even when the CPE is in a power-savemode.

In an embodiment of the invention, one or more logical channels may bededicated for the communication of special messages (e.g., messagespertaining to power management) and/or for the communication of trafficto “always-on” end systems, even when a CPE via which the “always-on”end system communicates is in a power-saving mode. For example, insystems utilizing DVB-C2 or DVB-T2, such traffic can be mapped to adedicated physical layer pipe.

FIG. 2 depicts a cable modem as an example of customer premise equipment(CPE). The cable modem 122 comprises a physical layer transceiver (PHY)module 202, DOCSIS medium access controller (MAC) module 204, EthernetMAC/PHY module 206, a TCP/IP stack module 208, a conditional accessmodule 210, and a host 218 comprising a CPU 216 and memory module 214which interoperate to execute applications/processes 212.

The PHY module 202 may be operable to receive digital signals from theMAC 204, generate corresponding analog symbols, and transmit the symbolsonto the WAN 118. Similarly, the PHY module 202 may be operable toreceive analog symbols over the WAN 118, convert the symbols to digitalsignals, and convey the digital signals to the MAC module 204. The PHYmodule 202 may be an instance of the PHY module 500 described below withrespect to FIG. 5A or the PHY module 550 described below with respect toFIG. 5B. The MAC module 204 may be operable to implement DOCIS mediaaccess control protocol(s) for regulating when and/or how the cablemodem 122 transmits on the WAN 118. The Ethernet MAC/PHY module 206 maybe operable to implement Ethernet physical layer and data link layerprotocols such that the cable modem 122 may transmit and receive via anEthernet local area network (LAN). The TCP/IP stack module 208 may beoperable to implement functionality of OSI layers 3 and higher layers toenable the host 218 to communicate via the WAN 118 and/or the LAN. Theconditional access module 210 may be operable to prevent the host fromtransmitting and/or receiving DOCSIS traffic via the WAN 118 if thecable modem 122 is not subscribed to such services. The CPU 216 mayexecute instructions stored in the memory module 214 and store run-timedata in the memory module 214 to execute various processes and/orapplications (e.g., an operating system).

In operation, a mode of operation of one or more components of the cablemodem 122 may be controlled via special messages which the PHY 202 maybe operable to decode, as described, for example, with respect to FIG.5A and/or FIG. 5B.

FIG. 3 depicts a cable set-top box as an example of customer premiseequipment (CPE). The set-top box 124 comprises a physical layertransceiver (PHY) module 302, a conditional access module 304, an MPEGdecoder module 306, audio digital-to-analog converter (DAC) module 308,and video encoder module 310.

The PHY module 302 may be operable to receive analog symbols over theWAN 118, convert the symbols to digital signals, and convey the digitalsignals to the MAC module 204. The PHY module 302 may be an instance ofthe PHY module 500 described below with respect to FIG. 5A or the PHYmodule 550 described below with respect to FIG. 5B. The conditionalaccess module 304 may be operable to prevent the set-top box 124 fromdecoding audio/video content to which it is not subscribed. The MPEGdecoder module 306 may be operable to decode MPEG streams carried in thesignal received via the WAN 118. The Audio DAC module 308 may beoperable to convert one or more digital audio signals output by the MPEGdecoder 306 into an analog signal for output to one or more speakers.The video encoder 310 may be operable to output one or more digitalvideo signals output by the MPEG decoder 306 according to one or morevideo protocols such as HDMI or DisplayPort.

In operation, a mode of operation of one or more components of theset-top box 124 may be controlled via special messages which the set-topbox 124 may be operable to decode, as described, for example, withrespect to FIG. 5A and/or FIG. 5B.

FIG. 4 depicts a cable gateway as an example of customer premiseequipment (CPE). The gateway 120 comprises a PHY module 402, a DOCSISMAC module 404, a conditional access module 406, a host controllermodule 408, an Ethernet MAC/PHY module 410, an MPEG decoder module 412,a video encoder module 414, and an audio DAC module 416.

The PHY module 402 may be operable to receive digital signals from theMAC 404, generate corresponding analog symbols, and transmit the symbolsonto the WAN 118. Similarly, the PHY module 402 may be operable toreceive analog symbols over the WAN 118, convert the symbols to digitalsignals, and convey the digital signals to the MAC module 404. The PHYmodule 402 may be an instance of the PHY module 500 described below withrespect to FIG. 5A or the PHY module 550 described below with respect toFIG. 5B. The MAC module 404 may be operable to implement DOCIS mediaaccess control protocol(s) for regulating when and/or how the gateway120 transmits on the WAN 118. The conditional access module 406 may beoperable to prevent the gateway 120 from decoding audio/video contentand/or data to which it is not subscribed. The host controller module408 may be operable to implement OSI layer 3 and higher OSI layers toenable communication between the WAN 118 and the LAN network via theEthernet MAC/PHY module 410. The Ethernet MAC/PHY module 410 may beoperable to implement Ethernet physical layer and data link layerprotocols such that the gateway 120 may transmit and receive via anEthernet local area network (LAN). The MPEG decoder module 412 may beoperable to decode MPEG streams carried in the signal received via theWAN 118. The Audio DAC module 416 may be operable to convert one or moredigital audio signals output by the MPEG decoder 412 into an analogsignal for output to one or more speakers. The video encoder 414 may beoperable to output one or more digital video signals output by the MPEGdecoder 412 according to one or more video protocols such as HDMI orDisplayPort.

In operation, a mode of operation of one or more components of thegateway 120 may be controlled via special messages which the gateway 120may be operable to decode, as described, for example, with respect toFIG. 5A and/or FIG. 5B.

FIG. 5A depicts an exemplary PHY of a CPE which supports low-power widearea networking. The PHY 500 comprises an analog front end (AFE) 502, atransmit chain 504, a demodulator module 506, a program identifier (PID)filter module 508, a first descrambler module 510, an address filtermodule 512, a second descrambler module 514, a message parser module516, a PID register 518, a global key register 520, an address register522, a local key register 524, a clock module 526, and a memory module528 for storing timing and/or state information.

For receive operations, the AFE 502 may be operable to amplify an analogsignal received via the WAN 118, down-convert the received signal,filter the received signal, convert the filtered signal to a digitalrepresentation, and convey the digital signal to the demodulator 506.For transmit operations, the AFE 502 may be operable to receive adigital signal from the transmit chain 504, convert the digital signalto an analog representation, filter the analog signal, up-convert thesignal, and amplify the signal for transmission onto the WAN 118.

The transmit chain 504 may be operable to perform operations to supporttransmission of data onto the WAN 118. Such operations may compriseencoding, modulating, converting to analog, filtering, and/or amplifyinga signal received from higher OSI layers.

The demodulator module 506 may be operable to demodulate the digitalsignal from the AFE 502 to recover an MPEG transport stream (MPEG-TS)contained therein.

The PID register 518 may store a PID which is utilized for MPEG-TSpackets which contain special messages for managing power consumption inthe network.

The program identifier (PID) filter module 508 may be operable to filterout (“drop”) MPEG-TS packets which have a PID that does not match thePID stored in the PID register 518.

The global key register 520 may store a descrambling key that enablesdescrambling at least a portion of each MPEG-TS packet passed by the PIDfilter 508. The global key stored in the register 520 may be common to,for example, all CPEs registered with the CMTS 114 and/or all CPEs whichare subscribed to a particular service provider.

The first descrambler module 510 may be operable to descramble,utilizing the key stored in the global key register 520, at least aportion (e.g., an address field) of each MPEG-TS packet that it receivesfrom the PID filter 508.

The address register 522 may store an address assigned to the CPE inwhich the PHY 500 resides. The address may be assigned, for example, bythe CMTS and/or a network administrator. In an exemplary embodiment, theaddress may be used only for communication of special messages (e.g.,messages for power management). That is, the address stored in theaddress register 522 may be the CPE's address only with respect toMPEG-TS packets having the PID stored in PID register 518; a differentaddress may, for example, be associated with the CPE for other types oftraffic.

The address filter module 512 may be operable to filter out (“drop”)MPEG-TS packets which have an address that does not match the addressstored in the address register 522.

The local key register 524 may store a descrambling key that enablesdescrambling at least a portion of one or more MPEG-TS packet output bythe address filter 512. The local key stored in the register 524 may beunique to, for example, the CPE in which the PHY 500 resides or to CPEsregistered with the CMTS 114.

The second descrambler module 514 may be operable to descramble,utilizing the key stored in the local key register 524, at least aportion (e.g., a payload) of one or more MPEG-TS packets that itreceives from the address filter 512.

The message parser module 516 may be operable to parse special messagescommunicated by the CMTS 114, and output corresponding instructionsand/or information onto the bus 520 for management of a mode ofoperation and/or power consumption of the CPE in which the PHY 500resides. The message parser 516 may, for example, comprise a sequencedetector, a look-up table, and/or a state machine.

The clock module 526 may be operable to generate one or more oscillatingsignals for synchronizing circuitry of the PHY 500 and/or for keepingtrack of time. The clock module 526 may, for example, comprise a realtime clock that enables scheduling events such as transitions into andout of a power-saving mode of operation.

The memory module 528 may be operable to store timing information suchas: times at which the CPE is to transition between different modes ofoperation, amount of time the CPE has been in a particular mode ofoperation, times at which a special message was received, times at whicha special message is expected, times at which to expect an upstreamchannel descriptor (UCD), times at which to expect a media access plan(MAP), etc. Additionally or alternatively, the memory module 528 maystore state information that may enable the PHY 500 to quickly resumecommunications upon waking from a power-saving mode. Such state info maycomprise, for example, upstream frequency to utilize for transmission,frequency on which to listen for reception, symbol rate at which totransmit, modulation profile, carrier offset, equalizer/filter settings,and/or gain settings. In an exemplary embodiment of the invention,before components of a CPE (e.g., a MAC of the CPE or portions of theCPE's PHY) go to sleep, those components may store state information tothe module 528. This information may be utilized upon the componentswaking from the power-saving mode to reduce the time necessary for thecomponents to be ready to receive data from the WAN 118.

In an exemplary embodiment, while the CPE is in power-save mode, the PIDfilter 508 may filter out any MPEG-TS packets not having a programidentifier (PID) indicating that they are a special message (the PIDstored in PID register 518). The MPEG-TS packets may be received via theWAN 118 which may be, for example, a cable television network, asatellite television network, a terrestrial television network, a DOCSISnetwork, a fiber to the X network, or any other suitable network. ForMPEG-TS packets having the PID stored in register 518, the firstdescrambler 510 may descramble an address of the MPEG-TS packetutilizing the key stored in to the register 520. The key may have been,for example, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. The descrambled address may then be compared to anaddress stored in the register 522. The address may have been, forexample, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. If the address is not a match, the packet may be droppedsince it is not directed to this CPE. If the address of the MPEG-TSpacket does match the address in the register 522, then the seconddescrambler 514 may descramble the payload of the MPEG-TS packetutilizing the key stored in the register 524. The key may have been, forexample, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. For messages that make it to the message parser 516, themessage parser 516 may parse the payload of the MPEG-TS packet torecover the special message contained therein. Data and/or instructionsbased on the special message may then be conveyed onto the powermanagement bus 530 (e.g., to be stored in memory, to updateregisters/parameters, etc.). The message may, for example, containinstructions for doing something now or later (e.g., “wake up now,”“wake up at time X,” or “wake up upon occurrence of event Y”).

In another exemplary embodiment, special messages may be sent in DOCSISpackets. Accordingly, the DOCSIS PID may be stored in the register 518and the PID filter 508 may compare the DOCSIS PID with the PID ofreceived MPEG-TS packets. If all packets transmitted on the channel havethe same DOCSIS PID, the PID may be absent and the PID filter 508 may bebypassed and/or confirm the absence of a PID. The first descrambler 510may descramble an address of the MPEG-TS packet utilizing the key storedin the register 520. The key may have been, for example, received by theCPE from the CMTS prior to the CPE entering low-power mode. Thedescrambled address may then be compared, by the address filter 512, tothe address stored in the register 522. The address may have been, forexample, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. If the address is not a match, the packet may be droppedsince it is not directed to this CPE. If the address of the MPEG-TSpacket does match the address stored in the register 522, then thesecond descrambler 514 may descramble the payload of the MPEG-TS packetutilizing the key stored in the register 524. The key may have been, forexample, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. The message parser 516 may then parse the DOCSIS packetto determine whether the packet contains a special message. If not, theMPEG-TS packet may be dropped. If the DOCSIS packet does contain aspecial message, the message parser 516 may process the DOCSIS packet torecover the special message. Data and/or instructions based on thespecial message may then be conveyed onto the power management bus 530(e.g., to be stored in memory, to update registers/parameters, etc.).The message may, for example, contain instructions for doing somethingnow or later (e.g., “wake up now,” “wake up at time X,” or “wake up uponoccurrence of event Y”).

In another exemplary embodiment, the special messages may be sent inhigher-layer protocol data units (PDUs) such as, for example, Ethernetframes. Accordingly, the DOCSIS PID may be stored in the register 518and the PID filter 508 may compare the DOCSIS PID stored in register 518with the PID of received MPEG-TS packets. If all packets transmitted onthe channel have the same DOCSIS PID, the PID may be absent and the PIDfilter 508 may be bypassed and/or confirm the absence of a PID. Thefirst descrambler 510 may descramble an address of the MPEG-TS packetutilizing the key stored in the register 520. The key may have been, forexample, received by the CPE from the CMTS prior to the CPE enteringlow-power mode. The descrambled address may then be compared, by theaddress filter 512, to the address stored in the register 522. Theaddress may have been, for example, received by the CPE from the CMTSprior to the CPE entering low-power mode. If the address is not a match,the packet may be dropped since it is not directed to this CPE. If theaddress of the MPEG-TS packet does match the address stored in theregister 522, then the second descrambler 514 may descramble the payloadof the MPEG-TS packet utilizing the key stored in the register 524. Thekey may have been, for example, received by the CPE from the CMTS priorto the CPE entering low-power mode. The message parser 516 may thenparse the DOCSIS packet to extract the higher-layer PDU (e.g., Ethernetframe), and may then parse the higher-layer PDU to determine whether itcontains a special message. If the higher-layer PDU does contain aspecial message, the message parser 516 may process the special message,and output, accordingly, data and/or instructions onto the powermanagement bus 530 (e.g., to be stored in memory, to updateregisters/parameters, etc.). The special message may, for example,contain instructions for doing something now or later (e.g., “wake upnow,” “wake up at time X,” or “wake up upon occurrence of event Y”).

Referring now to FIG. 5B, there is shown a PHY 550 which may reside in aCPE such as the cable modem 122, the set-top box 124, or the gateway120. The PHY 550 comprises an analog front end module 552, a digitalprocessing module 558, and a power management bus 530. The AFE 552comprises a signal path module 554 and a signal/sequence detect module556.

For receive operations, the signal path module 554 may be operable to,for example, amplify a received analog signal via the WAN 118,down-convert the received signal, filter the received signal, convertthe filtered signal to a digital representation, and convey the digitalsignal to the digital processing module 558. For transmit operations,the signal path module 554 may be operable to, for example, receive adigital signal from the digital processing module 558, convert thedigital signal to an analog representation, filter the analog signal,up-convert the signal, and amplify the signal for transmission onto theWAN 118.

The signal/sequence detect module 556 may comprise, for example, one ormore filters, comparators, and/or other components for detecting RFenergy having particular characteristics. The module 556 may be operableto detect, for example, energy over a determined period of time,voltage, sequence of voltages, frequency, sequence of frequencies, pulseduration, duty cycle, and/or sequence of duty cycles. Upon detecting adistinct signal/sequence that corresponds to a special message, thesignal/sequence detect module 556 may generate an interrupt, aninstruction, and/or other signal(s) to be conveyed on the powermanagement bus 530.

For receive operations, the digital processing module 558 may beoperable to process the output of the AFE 552 to recover data carried inthe received signals. Such processing may comprise, for example,demodulation, filtering, decoding, encoding, and/or digital to analogconversion. For transmit operations, the digital processing module 558may be operable to generate digital signals to be transmitted andprocess the signals for conveyance to the signal path 554. Suchprocessing may comprise, for example, modulation, filtering, and/orencoding.

In an exemplary embodiment, “special messages” may be communicated inthe form of physical layer signals (i.e., generated and/or processed atOSI layer 1). Such physical layer signals could comprise, for example, asimple synchronization signal. A physical layer special message could besent as an RF signal, or sequence of signals, having distinctcharacteristics (e.g., frequency, amplitude, duration) that indicate tothe receiver that it is a special message. For example, RF energy havinga particular frequency, amplitude, and/or duration could convey amessage that the CPE should, for example, wake up one or more of itscomponents (e.g., MAC, MPEG decoder, etc.) and/or put one or more of itscomponents (e.g., MAC, MPEG decoder, etc.) into a power-saving state.Additional distinct signals/sequences of RF energy could enableadditional messages. For example, a first distinct signal/sequence couldinstruct the CPE to sleep for a predetermined amount of time, a seconddistinct signal/sequence could instruct the CPE to sleep until itreceives a subsequent special message, a third distinct signal/sequencecould instruct the CPE to wake up now, etc. In an embodiment of theinvention, such physical layer special messages may be transmittedand/or received by the PHY without powering up other parts of the CPE,(e.g. the MAC). This can serve a number of purposes, including allowingthe CPE to function with very low duty cycle, thereby achieving very lowpower. As an example, a PHY may be operable to send an unencryptedsynchronization sequence with a predetermined PID.

In an embodiment of the invention, there may be a fixed and/ordeterministic time relationship between special messages and othercontrol messages (e.g., MAP and/or UCD) transmitted by the CMTS 114. Forexample, a special message to wake up a CPE may be sent a fixed and/ordeterministic amount of time before a MAP update. Accordingly, uponreceiving the special message, the CPE may begin counting down thisfixed and/or deterministic amount of time and then listen for a MAPupdate as the timer expires. The fixed and/or deterministic amount oftime may, for example, be preprogrammed into the network CPEs by anetwork administrator.

To support the low-power mode of operation of the CPE, the CMTS 114 mayneed to be configured such that it knows when a CPE is sleeping vs.powered-off. In this manner, the CMTS 114 may know not to de-registerthe CPE from the network while it is sleeping. By not de-registering theCPE, the CPE can more quickly resume communications on the network. TheCMTS 114 may implement a control policy for controlling, for example:when CPEs may sleep, how long CPEs should sleep, what events and/orconditions should cause CPEs to sleep or wake, etc. Inputs to thecontrol policy could include, for example, the status of buffers, thetime of day, the type of CPE (e.g., set-top box, modem, or gateway), thelevel of service of the client CPE (e.g., subscription level), userpreference, etc.

In an embodiment of the invention, the CMTS 114 may reserve some amountof bandwidth for a sleeping CPE. The reserved amount of bandwidth may beused, for example, to enable the CPE to come out of sleep mode on itsown, rather than waiting for a time agreed-upon with the CMTS 114 and/orinstead of waiting for a special message from the CMTS 114.

The CMTS 114 may support some initial messaging/communication with theCPE (e.g., cable modem 122) to coordinate sleep cycles of the CPE. Toenable a sleep mode in the CPE, the CMTS 114 may assign a PID to be usedwith the special messages and may notify the CPE of the assigned PID,may assign one or more descrambling/decryption keys (e.g., global andlocal descrambling keys) for processing special messages and may notifythe CPE of the assigned PID, and may assign an address to the CPE andnotify the CPE that it should look for special messages destined for theassigned address. Multiple CPEs, for example, could be given a commonaddress on which to receive special messages such that a single messagecould coordinate the sleep of the multiple CPEs. Similarly, differentaddresses may be assigned to different CPEs such that sleep cycles ofdifferent CPEs may be controlled differently. For example, the CMTS 114could stagger sleep intervals of groups of CPEs.

FIG. 6 illustrates an exemplary MAC of a CPE. The MAC 610 may be capableof operating in multiple modes of operation, with different modes ofoperation being characterized by different power consumption. In anexemplary embodiment, the MAC 610 may support a “normal” modecharacterized by higher power consumption and a “sleep” modecharacterized by lower power consumption, and may occasionally and/orperiodically be put into the sleep mode to reduce power consumption.

In some instances, the PHY (e.g., PHY 500 or 550) of a CPE may operatein a higher-power mode (i.e., be “awake”) while the MAC (e.g., MAC 610)of the CPE remains in a low-power mode (i.e., be “asleep”). During suchtimes, the PHY may resynchronize a clock utilized for transmittingsignals onto the WAN 118 to the clock utilized for receiving signals viathe WAN 118. Such synchronization may reduce the time needed to be readyto transmit upon the MAC transitioning out of the low-power mode.

In an exemplary embodiment of the invention, channel bonding as enabledin DOCSIS 3.0 may be controlled in coordination with the sleep cycle ofthe CPE. For example, while awake, a CPE may receive and/or transmit onmultiple channels, but while in a sleep mode, only one channel may beallocated for the CPE (the one channel could also be, for example,shared among multiple sleeping CPEs). Special messages may be utilizedto coordinate channel bonding.

FIG. 7 depicts a receive portion of a network device which is operableto communicate with customer premise equipment that supports apower-saving mode of operation. The receiver 700 comprises a low noiseamplifier (LNA) module 702, a mixer module 704, a filter module 706, ananalog-to-digital converter (ADC) 708, and a demodulator 710.

The low noise amplifier (LNA) 702 may be operable to amplify signalsreceived via the WAN 118. The mixer 704 may be operable down-convertreceived signals. The filter 706 may be operable to select one or moresub-bands of the received, down-converted signal. The analog-to-digitalconverter (ADC) 708 may be operable to convert the analog signal outputby filter 706 to a digital representation. The demodulator 710 may bethe same as the demodulator 506 and may be operable to demodulate thedigital signal from the ADC 708 to recover an MPEG transport stream(MPEG-TS) contained therein.

In operation, a mode of operation of various components (e.g., amplifier702, mixer 704, filter 706, data converter 708, and demodulator 710) ofthe receiver 700 may be controlled based on whether the receiver 700 isreceiving, or expecting to receive, messages from a CPE in a normal modeof operation or a CPE in a low-power mode of operation. In this regard,the receiver 700 may be operable to receive a first type of message fromdevices operating in a low-power mode, and a second type of message fromdevices not operating in a low-power mode. An example of the first typeof message is a “heartbeat” or other special message indicating that aCPE is still connected but in a low-power mode. An example of the secondtype of message is a conventional MPEG-TS packet communicated in aconventional DOCSIS network. Messages of the first type (e.g., “specialmessages” for managing power consumption and modes of operation) mayhave different characteristics than messages of the second type. Forexample, the different message types may be modulated differently, usedifferent interleaver depth, have different timing, different amplitude,etc. Accordingly, one or more of the components 702-710 may beconfigured, via the bus 701, into a first configuration for receivingmessages of the first type (messages from devices operating in alow-power mode), and into a second configuration for receiving messagesof the second type (messages from devices not operating in a low-powermode).

FIG. 8 depicts a portion of a transmitter of a network device which isconfigurable based on a mode of operation of a customer premise deviceto which the network device is transmitting. The transmitter 800comprises a power amplifier (PA) module 802, a mixer module 804, afilter module 806, a digital-to-analog converter (DAC) 808, and amodulator 810.

The power amplifier (PA) 802 may be operable to amplify signals fortransmission onto the WAN 118. The mixer 804 may be operable up-convertsignals to be transmitted. The filter 806 may be operable to filter outundesired signals output by the DAC 808. The DAC 808 may be operable toconvert the digital signal output by modulator 810 to an analogrepresentation.

The modulator 810 may be operable to modulate a MPEG transport streamonto a carrier. In an exemplary embodiment, hierarchical modulation maybe utilized for multiplexing multiple data streams into a single symbolstream. A first one of the data streams may be a low-bandwidth streamcomprising, for example, special messages, and a second one of thestreams may be a high-bandwidth stream comprising, for example, normalDOCSIS traffic (i.e., messages other than the special messages). Themodulator 810 may utilize, for example, QPSK modulation with lowerinterleaver depth for transmitting the first stream, while utilizing,for example, 64QAM or 256QAM modulation with higher interleaver depthfor transmitting the second stream.

In operation, a mode of operation of various components (e.g., amplifier802, mixer 804, filter 806, data converter 808, and modulator 810) ofthe transmitter 800 may be controlled based on the type of message thatthe transmitter 800 is transmitting. In this regard, a first type ofmessage may be transmitted when communicating with customer premiseequipment in a power-saving mode, and a second type of message may betransmitted when communicating with customer premise equipment not in apower-saving mode. An example of the first type of message is a “wakeup” or other special message instructing the CPE to transition out of alow-power mode. An example of the second type of message is aconventional MPEG-TS packet communicated in a conventional DOCSISnetwork. The different types of messages may have differentcharacteristics. For example, the different message types may bemodulated differently (e.g., different modulation order), use differentinterleaver depth, have different timing, different amplitude, etc.Accordingly, one or more of the components 802-810 may be configured,via the bus 801, into a first configuration for receiving messages ofthe first type (messages from devices operating in a low-power mode),and into a second configuration for receiving messages of the secondtype (messages from devices not operating in a low-power mode).

FIG. 9 is a flowchart illustrating exemplary steps for managing powerconsumption via special messaging. For illustration, the steps aredescribed with reference to cable modem 122 and CMTS 114, but are notlimited to any particular devices. In step 902, the CMTS 114 and thecable modem 122 are operating in a normal mode of operation and mayexchange message(s) (of a first type) to coordinate the cable modem 122transitioning to a low-power mode without being de-registered by theCMTS 114.

In step 904, the CMTS 114 sends one or more of the following to thecable modem 122: a PID associated with special messages; keys fordescrambling special messages; an address to be associated with thecable modem 122 for the purposes of special messages. The valuesreceived in step 904 may be stored in the registers 518-524.

In step 906, prior to transitioning to a low-power state of operation,the cable modem 122 stores state and/or timing information to the memorymodule 528. At a later time, when the cable modem 122 transitions backto a normal mode of operation, the stored state and/or timinginformation may enable the cable modem 122 to quickly resynchronizeand/or recalibrate settings and/or parameters which may have becomestale as a result of, for example, the cable modem 122 missing upstreamchannel descriptors, missing MAP updates, and not performing stationmaintenance (ranging) during the period that the cable modem 122 was inthe low-power mode.

In step 908 the cable modem 122 transitions to a low-power mode. Whilein the low-power mode, communications between the cable modem 122 andCMTS 114 may be limited to reception and/or transmission of messages ofa second type (“special” or “power management” messages). Accordingly,while the cable modem 122 is in sleep mode, the CMTS 114 may beconfigured to transmit messages of the second type when transmitting tothe cable modem 122 and to receive messages of the second type whenlistening for messages from the cable modem 122.

In step 910 the CMTS 114 generates a message of the second typeutilizing the PID, scrambling keys, and address communicated to thecable modem 122 in step 904. The CMTS 114 may transmit the message tothe cable modem 122 via the WAN 118.

In step 912, the cable modem 122 receives and detects the messagetransmitted in step 910. In an exemplary embodiment, the cable modem 122may generate and send a message of the second type to acknowledgereceipt of the message sent in step 910.

In step 914, the cable modem 122 wakes up in accordance with the messagereceived in step 912. For example, if the special message is a “wake upnow” message, the cable modem 122 may immediately begin a transition outof the low-power mode (e.g., reads state information out of memorymodule 528. As another example, if the message is a “wake up in Xseconds” message, the cable modem 122 may set a countdown timer to valueX seconds and immediately begin a transition out of the low-power modeupon expiration of the timer.

In step 916, as part of the transition to a normal mode of operation,the cable modem 122 may utilize state information from the memory module528 to recalibrate and/or resynchronize one or more components.

In step 918, the cable modem 122 may resume transmission and receptionof traffic other than special messages.

FIG. 10 is a flowchart illustrating exemplary steps performed in alow-power wide area network. For illustration, the steps are describedwith reference to cable modem 122 and CMTS 114, but are not limited toany particular devices. In step 1002, the CMTS 114 and the cable modem122 may exchange messages (e.g., messages of a first type) to coordinatethe cable modem 122 sleeping for a period of time without beingde-registered by the CMTS 114. In step 1004, while the cable modem 122is sleeping, the CMTS 114 buffers packets to be sent to the cable modem122. In step 1006, the CMTS 114 determines to wake up the cable modem122 based on a power management control policy in place in the network.In step 1008, the CMTS 114 generates a message (e.g., message of asecond type to wake up the cable modem and sends it to the cable modem122. In step 1010, the CMTS 114 waits for a message of a first typeindicating that the cable modem 122 has transitioned out of thelow-power mode and/or for a message of a second type indicating that thecable modem 122 will transition out of the power-saving mode. If such amessage does not arrive within a determined amount of time, then thesteps may return to step 1008. Conversely, if such a message isreceived, the exemplary steps may advance to step 1012. In step 1012,the CMTS 114 and cable modem 122 may resume normal communications ofexchanging MPEG-TS packets.

FIG. 11 is a flowchart illustrating exemplary steps performed in alow-power wide area network. For illustration, the steps are describedwith reference to cable modem 122 and CMTS 114, but are not limited toany particular devices. In step 1102, the CMTS 114 and the cable modem122 may exchange messages of a first type to coordinate the cable modem122 sleeping for a period of time without being de-registered by theCMTS 114. In step 1104, while the cable modem 122 is sleeping, the CMTS114 sends a message of a second type instructing the cable modem 122 towake up at time X. In step 1106, prior to time X, high-priority trafficmay be generated by the host 218 and/or received by the cable modem 122via the Ethernet MAC/PHY 206. In step 1108, in response to the need tosend the high-priority traffic, the cable modem 122 may wake up andcommunicate (e.g., using message(s) of the second type) with the CMTS114 to inform the CMTS 114 that the cable modem 122 has exited thepower-saving mode early.

FIG. 12A is a flowchart illustrating exemplary steps managing deviceregistration in a low-power wide area network. In step 1202, the CMTS114 has not heard from a customer premise device for more than apredetermined amount of time. In response, in step 1204, the CMTS 114sends a message (e.g., of a second type) to verify that the customerpremise device is sleeping (and has not been disconnected). In step1206, if the CMTS 114 receives a reply to the message sent in step 1204,then in step 1210 the CMTS 114 may maintain the registration of thecustomer premise device in question. If the CMTS 114 does not receive areply, then in step 1208 the CMTS 114 may deregister the customerpremise device in question.

FIG. 12B is a flowchart illustrating exemplary steps managing deviceregistration in a low-power wide area network. In step 1222, after startstep 1220, the CMTS 114 and the cable modem 122 may exchange messages(e.g., messages of a first type) to coordinate the cable modem 122sleeping until time X. In step 1224, at time X+Δ, where Δ is the amountof time required for the cable modem 122 to wake up and transmit, theCMTS 114 may listen for a message from the cable modem 122 indicatingthat the cable modem 122 has exited the low-power mode. If the CMTS 114does not receive such a message, then in step 1228 the cable modem 122may be deregistered. If the CMTS 114 does receive such a message, thenthe cable modem 122 may remain registered.

Other embodiments of the invention may provide a non-transitory computerreadable medium and/or storage medium, and/or a non-transitory machinereadable medium and/or storage medium, having stored thereon, a machinecode and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for a low-powerwide area network.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A system comprising: a network device whichmanages a network connection of customer premise equipment, wherein:while said customer premise equipment is operating in a normal mode ofoperation, said network device communicates with said customer premiseequipment utilizing one or more messages of a first type, wherein saidone or more messages of said first type comprise an MPEG transportpacket not having a particular program identifier; and while saidcustomer premise equipment is operating in a low-power mode ofoperation, said network device communicates with said customer premiseequipment utilizing one or more messages of a second type, wherein saidone or more messages of said second type comprise an MPEG transportpacket having said particular program identifier.
 2. The system of claim1, wherein said network device is a cable modem termination system andsaid customer premise equipment is a cable modem.
 3. The system of claim1, wherein: said one or more messages of said first type comprise anMPEG transport packet having a first value in a destination addressfield; and said one or more message of said second type comprises anMPEG transport packet having a second value in said destination addressfield.
 4. The system of claim 1, wherein said one or more messages ofsaid first type instruct said customer premise equipment to enter saidlow-power mode.
 5. The system of claim 1, wherein said one or moremessages of said second type instruct said customer premise equipment toexit said low-power mode.
 6. The system of claim 1, wherein a modulationscheme used for generating said one or more messages of said first typeis of a higher-order than a modulation scheme used for generating saidone or more messages of said second type.
 7. The system of claim 1,wherein an interleaver depth used for generating said one or moremessages of said first type is larger than an interleaver depth used forgenerating said one or more messages of said second type.
 8. The systemof claim 1, wherein said network device is operable to distinguishbetween: (i) said customer premise equipment that is powered-off and/ordisconnected from said network device; and (ii) said customer premiseequipment that is in said low-power mode.
 9. The system of claim 8,wherein said network device is operable to: deregister said customerpremise equipment when said customer premise equipment is powered-offand/or disconnected from said network device; and maintain aregistration of said customer premise equipment when said customerpremise equipment is in said low-power mode.
 10. The system of claim 1,wherein: said message of said first type comprises an MPEG transportpacket; and said message of said second type comprises non-packetized,physical layer signals.
 11. The system of claim 1, wherein: while saidcustomer premise equipment is operating in said normal mode ofoperation, said network device is configured to receive messages of afirst type from said customer premise equipment; and while said customerpremise equipment is operating in said low-power mode of operation, saidnetwork device is configured to receive messages of a second type fromsaid customer premise equipment.
 12. A method comprising: performing bya network device: determining a particular program identifier to beutilized for messages that manage power consumption of one or morecustomer premise devices coupled to said network device; andtransmitting one or more messages to said one or more customer premisedevices, wherein: the portion of said one or more messages that aretransmitted while said one or more customer premise devices are in alow-power mode comprises MPEG transport packets having said particularprogram identifier; and the portion of said one or more messages thatare transmitted while said one or more customer premise devices are notin said low-power mode comprises MPEG transport packets not having saidparticular program identifier.
 13. The method of claim 12, wherein saidnetwork device comprises a cable modem termination system (CMTS) andsaid one or more customer premise devices comprise one or more cablemodems.
 14. The method of claim 12, wherein: the portion of said one ormore messages that are transmitted while said one or more customerpremise devices are in a low-power mode comprises MPEG transport packetshaving a first value in a destination address field; and the portion ofsaid one or more messages that are transmitted while said one or morecustomer premise devices are not in said low-power mode comprises MPEGtransport packets having a second value in said destination addressfield.
 15. The method of claim 12, wherein said one or more transmittedmessages control when said one or more customer premise devices are insaid low-power mode and when said one or more customer premise devicesare not in said low-power mode.
 16. The method of claim 15, wherein saidnetwork device controls when said one or more customer premise devicesare in said low-power mode based on the status of one or more buffers inthe network device.
 17. The method of claim 15, wherein said networkdevice controls when said one or more customer premise devices are insaid low-power mode based on a real time clock of said network device.18. The method of claim 15 wherein said network devices controls whensaid one or more customer premise devices are in said low-power modebased on the level of service to which said one or more customer premisedevices are subscribed.
 19. The method of claim 15, comprising:determining whether said one or more customer premise devices are: (i)in said low-power mode or (ii) powered off and/or disconnected from saidnetwork device; maintaining a registration of said one or more customerpremise devices if said one or more customer premise devices are in saidlow-power mode; and deregistering said one or more customer premisedevices if said one or more customer premise devices are powered off ordisconnected from said network device.